I just did this exact setup with the same blower you have. You can get the linkage brackets directly from MTD.
Unfortunately I ordered 2, but you only need 1. There are 2 linkage brackets, but only 1 needs to be replaced with this part. Only 1 is adjustable which is the one that must be replaced. The other side uses the same one which is used for the deck. I have used mine twice now and am very happy with the performance. I have a 1995 Yard Machines by MTD 16HP/42. I have a few posts on here about it if you search for 190-491. If you need any help figuring things out just let me know. I spent some time figuring this out, but got it done and it works perfectly.